1. Field of the Invention
This invention relates generally to gas turbine engines and, more particularly, to a method and apparatus for controlling the power and minimizing the fan-radiated noise of a turbofan engine.
2. Description of the Prior Art
Prior art engine control systems have controlled engine operation primarily by regulating engine fuel flow in order to produce a desired level of thrust. Various other engine components, such as exhaust nozzles, have sometimes been manipulated by separate controls, again primarily for the purpose of regulating the thrust level. Little, if any, intercommunication has been provided between the fuel control and the controls for the various other engine components.
Present-day aircraft propulsion systems are required to operate efficiently over a wide range of engine altitudes and thrust levels while maintaining engine noise below certain maximum limits. Since prior art engine control systems were designed primarily for regulating only the engine thrust level, they do not have the inherent capability of simultaneously minimizing the engine noise.
It is therefore an object of the present invention to provide an integrated gas turbine engine control system which maintains low engine noise levels while producing desired thrust-setting accuracy and rapid thrust response.
Another object of the present invention is to provide such a control system which operates automatically.
A further object of the present invention is to provide such a control system which utilizes more fully and efficiently existing engine components.